Conventionally, there are various types of so-called non-contact ID cards, non-contact tags, and the like (referred to as non-contact ID cards hereinafter) wherein an IC chip is mounted on an antenna circuit board.
An example may be that of a non-contact ID card, comprised of an antenna circuit board in which the antenna is formed on a substrate, and an interposer board in which an enlarged electrode connected to an electrode of an IC chip is formed on a substrate on which the IC chip is mounted. Both boards are then laminated in such a way that the electrode of the antenna and the enlarged electrode conduct electricity (for an example, refer Patent Document 1). In this non-contact ID card, the electrode of the antenna and the enlarged electrode conduct electricity by bonding (referred to as adhesive bonding hereinafter) through conductive adhesive or conductive pressure-sensitive adhesive, or the electrode of the antenna and the enlarged electrode conduct electricity by being in close contact without any adhesive (referred to as a non-adhesive bonding).
However, in the above-mentioned adhesive bonding, paste or film-tape conductive adhesive or conductive pressure-sensitive adhesive needs to be applied or stuck to one of the micro electrodes, which is complicated and difficult to perform within a short time frame. In addition, the bond is prone to being displaced. Therefore, improvements are necessary for productivity, the electrical properties, and such like. The above-mentioned non-adhesive bonding bonds both substrates without using any conductive adhesive or conductive pressure-sensitive adhesive, and maintains both electrodes in close contact thereby. Hence, productivity is better when compared to the above-mentioned adhesive bonding. However, the electrical properties are inferior as conductivity between both electrodes is unstable.
There have been some methods experimented with where the electrode of the antenna and the enlarged electrode are adhesively bonded together and at the same time both substrates are bonded together, and where both electrodes are not regular metal electrodes but at least one is made of resin which is formed by the conductive adhesive. However, the aforementioned shortcomings have not yet been sufficiently overcome.
Patent Document 1: International Publication WO 01/62517 pamphlet